BackgroundIn anticipation of applying Appropriate Use Criteria for percutaneous coronary intervention (PCI) quality improvement, we determined the prevalence of appropriate, uncertain, and inappropriate PCIs stratified by indication for all PCIs performed in the state of Washington.Methods and ResultsWithin the Clinical Outcomes Assessment Program, we assigned appropriateness ratings to all PCIs performed in 2010 in accordance with published Appropriate Use Criteria. Of 13 291 PCIs, we successfully mapped the clinical scenario to the Appropriate Use Criteria in 9924 (75%) cases. Of the 3367 PCIs not classified, common failures to map to the criteria included nonacute PCI without prior noninvasive stress results (n=1906; 57%) and unstable angina without high-risk features (n=902; 27%). Of mapped PCIs, 8010 (71%) were for acute indications, with 7887 (98%) rated as appropriate, 39 (<1%) as uncertain, and 84 (1%) as inappropriate. Of 1914 mapped nonacute indications, 847 (44%) were rated as appropriate, 748 (39%) as uncertain, and 319 (17%) as inappropriate. Assuming results for noninvasive stress tests when data were missing, in the best-case scenario, 319 (8%) of nonacute PCIs were classified as inappropriate compared with 1459 (38%) in the worst-case scenario. Variation in inappropriate PCIs by facility was greatest for mapped nonacute indications (median=14%; 25(th) to 75(th) percentiles=9% to 24%) and nonacute indications with missing data precluding appropriateness classification (median=54%; 25(th) to 75(th) percentiles=35% to 66%).ConclusionsIn a complete cohort of PCIs performed in Washington state, 1% of PCIs for acute indications and 17% of PCIs for nonacute indications were classified as inappropriate. Missing data on noninvasive stress tests present a challenge in the application of the criteria for quality improvement.